ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-10-22339-2010 Three-year observations of halocarbons at the Nepal Climate Observatory at Pyramid (NCO-P, 5079 m a.s.l.) on the Himalayan range Maione M. 1 6 Giostra U. 2 6 Arduini J. 1 6 Furlani F. 2 6 Bonasoni P. 3 Cristofanelli P. 3 Laj P. 4 Vuillermoz E. 5 University of Urbino, Institute of Chemical Sciences, Urbino, Italy University of Urbino, Dept. of Physics, Urbino, Italy CNR-Institute for Atmospheric Sciences and Climate, Bologna, Italy Laboratoire de Glaciologie et Géophysique de l'Environnement, Université Grenoble 1-CNRS, Grenoble, France Ev-K<sup>2</sup>-CNR Committee, Bergamo, Italy CINFAI, National Consortium of Universities for Atmospheric and Hydrospheric Physics, Italy 28 09 2010 10 9 22339 22368 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/10/22339/2010/acpd-10-22339-2010.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/10/22339/2010/acpd-10-22339-2010.pdf

A monitoring programme for halogenated climate-altering gases has been established in the frame of the SHARE EV-K<sup>2</sup>-CNR project at the Nepal Climate Laboratory – Pyramid in the Himalayan range at the altitude of 5079 m a.s.l. The site is very well located to provide important insights on changes in atmospheric composition in a region that is of great significance for emissions of both anthropogenic and biogenic halogenated compounds. Measurements are performed since March 2006, with grab samples collected on a weekly basis. The first three years of data have been analysed. After the identification of the atmospheric background values for fourteen halocarbons, the frequency of occurrence of pollution events have been compared with the same kind of analysis for data collected at other global background stations. The comparison with time series from other stations has also allowed to derive Meridional gradients, which are absent for long living well mixed species, while for the more reactive species, the gradient increases inversely with respect to their atmospheric lifetime. The effect of long range transport and of local events on the atmospheric composition at the station has been analysed as well, allowing the identification of relevant source regions the Northern half of the Indian sub-continent. Also, at finer spatial scales, a smaller, local contribution of forest fires from the Khumbu valley has been detected.

 References Andreae, M. O., Atlas, E., Harris, G. W., Helas, G., de Kock, A., Koppmann, R., Maenhaut, W., Mano, S., Pollock, W. H., Rudolph, J., Scharffe, D., Schebeske, G., and Welling, M.: Methyl Halide emissions from savannah fires in southern Africa, J. Geophys. Res., 101, 23603–23613, 1996. Bonasoni, P., Laj, P., Bonafè, U., Calzolari, F., Cristofanelli, P., Marinoni, A., Roccato, F., Facchini, M. C., Fuzzi, S., Gobbi, G. P., Pichon, J. M., Venzac, H., Sellegri, K., Villani, P., Maione, M., Arduini, J., Petzold, A., Sprenger, M., Verza, G. P., and Vuillermoz, E.: The ABC-Pyramid: a scientific laboratory at 5079 m a.s.l. for the study of atmospheric composition change and climate. in: Mountains witnesses of global changes research in the Himalaya and Karakoram; SHARE- Asia project, Developments in Earth Surface Processes, edited by: Baudo, R., Tartari, G., and Vuillermoz, E., Elsevier, Amsterdam, 67-73, 65, Chapter 10, 2007. Bonasoni, P., Laj, P., Marinoni, A., Sprenger, M., Angelini, F., Arduini, J., Bonafè, U., Calzolari, F., Colombo, T., Decesari, S., Di Biagio, C., di Sarra, A. G., Evangelisti, F., Duchi, R., Facchini, M. C., Fuzzi, S., Gobbi, G. P., Maione, M., Panday, A., Roccato, F., Sellegri, K., Venzac, H., Verza, G. P., Villani, P., Vuillermoz, E., and Cristofanelli, P.: Atmospheric Brown Clouds in the Himalayas: first two years of continuous observations at the Nepal-Climate Observatory at Pyramid (5079 m), Atmos. Chem. Phys. Discuss., 10, 4823–4885, doi:10.5194/acpd-10-4823-2010, 2010. Butler, J. H., Battle, M., Bender, M., Montzka, S. A., Clarke, A. D., Saltzman, E. S., Sucher, C., Severinghaus, J., and Elkins, J. W.: A twentieth century record of atmospheric halocarbons in polar firn air, Nature, 399, 749–755, 1999. Cox, M. L., Paul, J., Fraser, P. J., Sturrock, G. A., Siems, S. T., and Porter, L. W.: Terrestrial sources and sinks of halomethanes near Cape Grim, Tasmania, Atmos. Environ., 38, 3839–3852, 2004. Clerbaux, C. and Cunnold, D.M. (Lead Authors), Anderson, J., Engel, A., Fraser, P. J., Mahieu, E., Manning, A., Miller, J., Montzka, S. A., Nassar, R., Prinn, R., Reimann, S., Rinsland, C. P., Simmonds, P., Verdonik, D., Weiss, R., Wuebbles, D., and Yokouchi, Y.: Long-Lived Compounds, Chapter 1 in Scientific Assessment of Ozone Depletion: 2006, Global Ozone Research and Monitoring Project report no. 50, World Meteorological Organization, Geneva, Switzerland, 2007. Hastie, T., Tibshirani, R., and Friedman, J.: Data Mining, Inference, and Prediction, Springer-Verlag, New York, 2001. Giostra, U.: The determination of a "European" atmospheric background mixing ratio for anthropogenic greenhouse gases: comparison of two independent methods, 2010. Greally, B. R., Manning, A. J., Reimann, S., Mcculloch, A., Huang, J., Dunse, B. L., Simmonds, P. G., Prinn, R. G., Fraser, P. J., Cunnold, D. M., O'doherty, S., Porter, L. W., Sturrock, G. A., Stemmler, K., Vollmer, M. K., Lunder, C. R., Schmidbauer, N., Hermansen, O., Arduini, J., Salameh, P. K., Krummel, P. B., Wang, R. H. J., Folini, D., Weiss, R. F., Maione, M., Nickless, G., Stordal, F., and Derwent, R. G.: Observation of 1,1-difluoroethane (HFC-152a) at AGAGE and SOGE monitoring stations 1994–2004 and derived Global and regional emission estimates, J. Geophys. Res., 112, D06308, doi:10.1029/2006JD007527, 2007. IPCC/TEAP: Special Report on Safeguarding the Ozone Layer and the Global Climate System: Issues Related to Hydrofluorocarbons and Perfluorocarbons, edited by: Metz, B., Kuijpers, L., Solomon, S., et al., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 488~pp, 2005. Maione, M., Arduini, J., Mangani, G., and Geniali, A.: Evaluation of an Automated Gas Chromatographic – Mass Spectrometric Instrumentation to be Used for Continuous Monitoring of Trace Anthropogenic Greenhouse Gases, Internat. J. Environ. Anal. Chem., 84(4), 241–253, 2004. Maione, M., Giostra, U., Arduini, J., Belfiore, L., Furlani, F., Geniali, A., Mangani, G., Vollmer, M. K., and Reimann, S.: Localization of source regions of selected hydrofluorocarbons combining data collected at two European mountain Stations, Sci. Total Environ., 391, 232–240, 2008. Moore, R. M., Webb, M., Tokarczyk, R., and Weaver, R.: Bromoperoxidase and iodoperoxidase enzymes and production of halogenated methanes in marine diatom cultures, J. Geophys. Res., 101, 20899–20908, 1996. Motzka, S., Butler, J., Hall, B., Mondeel, D., and Elkins, J.: A decline in tropospheric organic bromine, Geophys. Res. Lett., 30, 1826–1829, 2003. Ramanathan, V., Li, F., Ramana, M. V., Siva, P. S., Kim, D., Corrigan, C. E., Nguyen, H., Stone, E. A., Schauer, J. J., Carmichael, G. R., Adhikary, B., and Yoon, S. C.: Atmospheric Brown Clouds: Hemispherical and regional variations in long range transport, absorption and radiative forcing , J. Geophys. Res., 112, D22S21, doi:10.1029/2006JD008124, 2007. Ramanathan, V. and Feng, Y.: Air pollution, greenhouse gases and climate change: global and regional perspective, Atmos. Environ., 43, 37–50, 2009. Redeker, K. R., Wang, N.-Y., Low, J. C., McMillan, A., Tyler, S. C., and Cicerone, R. J.: Emissions of methyl halides and methane from rice paddies, Science, 290, 966–969, 2000. Reimann, S., Schaub, D., Stemmler, K., Folini, D., Hill, M., Hofer P., Buchmann, B., Simmonds, P. G., Greally, B., and O'doherty, S.: Halogenated greenhouse gases at the Swiss High Alpine Site of Jungfraujoch (3580 m asl). Continuous measurements and their use for regional European source allocation, J. Geophys. Res., 109, D05307, doi:10.1029/2003JD003923, 2004. Reimann, S., Manning, A. J., Simmonds, P. G., Cunnold, D. M., Wang, R. H., Li, J., McCulloch, A., Prinn, R. G., Huang, J., Weiss, R. F., Fraser, P. J., O'Doherty, S., Greally, B. R., Stemmler, K., Hill, M., Folini, D.: Low European methyl chloroformemissions inferred from long-term atmospheric measurements, Nature, 433, 506–508, 2005, doi:10.1038/nature03220. Rudolph, J. A., Khedim, R., Koppman, R., Bonsang, B.: Field study of the emissions of methyl chloride and otherhalocarbons from biomass burning in western Africa, J. Atmos. Chem., 22, 67–80, 1995. Ryall, D. B., Derwent, R. G., Manning, A. J., Simmonds, P. G., and O'Doherty, S.: Estimating source regions of European emissions of trace gases from observations at Mace Head, Atmos. Environ., 35, 2507–2523, 2001. Rudolph, J., Khedim, A., Koppmann, R., and Bonsang, B.: Field study of the emissions of methyl chloride and other halocarbons from biomass burning in western Africa, J. Atmos. Chem., 22, 67–80,1995. Trudinger, C. M., Etheridge, D. M., Sturrock, G. A., Fraser, P. J., Krummel, P. B., and McCulloch, A.: Atmospheric histories of halocarbons from analysis of Antarctic firn air: Methyl bromide, methyl chloride, chloroform, and dichloromethane, J. Geophys. Res., 109, D22310, doi:10.1029/2004JD004932, 2004. UNEP (United Nations Environment Programme), The Montreal Protocol on substances that deplete the ozone layer, Montreal and subsequent amendements, 1987. UNFCCC (United Nations Framework Convention on Climate Change), The Kyoto Protocol on Climate Change, Kyoto, 1997. Wernli, H. and Davies, H.: A Lagrangian-based analysis of extratropical cyclones. Part I: The method and some applications, Q. J. Roy. Meteorol. Soc., 123, 467–489, 1997. Xiao, X., Prinn, R. G., Fraser, P. J., Simmonds, P. G., Weiss, R. F., O'Doherty, S., Miller, B. R., Salameh, P. K., Harth, C. M., Krummel, P. B., Porter, L. W., Mühle, J., Greally, B. R., Cunnold, D., Wang, R., Montzka, S. A., Elkins, J. W., Dutton, G. S., Thompson, T. M., Butler, J. H., Hall, B. D., Reimann, S., Vollmer, M. K., Stordal, F., Lunder, C., Maione, M., Arduini, J., and Yokouchi, Y.: Optimal estimation of the surface fluxes of methyl chloride using a 3-D global chemical transport model, Atmos. Chem. Phys., 10, 5515–5533, doi:10.5194/acp-10-5515-2010, 2010. Yokouchi, Y., Machida, T., Barrie, L. A., Toom Sauntry, D., Nojiri, Y., Fujinuma, Y., Inuzuka, Y., Li, H.-J., Akimoto, H., and Aoki, S.: Latitudinal distribution of atmospheric methyl bromide: measurements and modelling, Geophys. Res. Lett. 27, 697–700, 2000. Yokouchi, Y., Ikeda, M., Inuzuka, Y., and Yukawa, T.: Strong emission of methyl chloride from tropical plants, Nature, 416, 163–165, 2002.